The present invention relates to a motor-vehicle door latch device.
A door latch device in a motor vehicle comprises a latch that is mounted via a shaft to a base member fixed to a liftgate and disengages from a striker of a vehicle body from a full-latch position where the liftgate is fully closed to an open position; an engagement member such as a pawl or a ratchet that engages a full-latch engaging portion of the latch to hold the latch in the full-latch position; and a releasing lever actuated with a door-opening unit to turn the engagement member to disengage the engagement member from the full-latch engaging portion.
In the door latch device, a half-latch position is set in which even if the latch should be disengaged from the engagement member when the latch is in the full-latch position, the door is held in a incompletely-closed state by engaging the engagement member with a half-latch engaging portion between the full-latch position and the open position so as not to open the liftgate accidentally.
In the door latch device in which the half-latch position is set, for example, when the liftgate is opened and closed by a switch for an electric actuator for opening the door and a lever for opening the door in a driver's seat, the engagement member engages with the half-latch engaging portion in the half-latch position to hold the liftgate in a half-open state due to lack in raising of the liftgate because repulsion of a weatherstrip decreases or the circumference around the liftgate is frozen, the liftgate cannot be opened by a single opening action.
It is necessary to disengage the latch from the engagement member by operating the switch or lever again, which is troublesome.
JP2001-329731A and JP3143586B2 disclose a door latch device and a door lock device respectively for overcoming the foregoing disadvantage.
In the door latch device in JP2001-329731A, when the opening lever is actuated to open the door, the pawl is turned by the opening lever in a direction for disengaging from the latch. When the opening lever is operated to the releasing end of the door, a holding lever engages with the opening lever, and the pawl is held in a position where the pawl does not engage with the half-latch engaging portion and full-latch engaging portion.
In the door lock device in JP3143586B2, a half-latch preventing plate has an arcuate projection around the latch shaft, and the ratchet has a projection-having half-preventing lever which moves with the ratchet when the ratchet disengages from a full-latch engagement step by opening the door. When the door is opened, the half-latch engagement step does not engage with the ratchet so that the projection on the projection-having half-preventing lever does not return beyond the arcuate projection.
In the door latch device in which the half-latch position is set, when the door is closed, the engagement member engages with the half-latch engaging portion due to repulsion of a weatherstrip, and the door is incompletely closed. The liftgate cannot be closed by a single door-closing action.
In view of the disadvantage, there are a door-opening half-latch avoiding unit for preventing the latch from being held in the half-latch position when the door is opened, and a door-closing half-latch avoiding unit for preventing the latch from being held in the half-latch position when the door is closed. The two units are selectively installed to provide a door latch device for preventing the latch from being held in the half-latch position when the door is closed, and a door latch device for preventing the latch from being held in the half-latch position when the door is opened. One of the two door latch devices can readily be provided depending on demand of customers.
However, in order to apply the door latch device and the door lock device in JP2001-329731A and JP3143586B2 respectively to a door latch device for preventing the latch from being held in the half-latch position when the door is closed, it is necessary to change and modify the shape and position of each element.